This invention relates to cam systems for knitting machines, and is particularly directed to the provision of an improved arrangement permitting the changing of the position of cam surfaces as well as interchanging cams in a cam retainer of circular knitting machines.
In one arrangement enabling the rapid attachment of a cam carrier on a cam retainer, or a cam retainer on its cam carrier, bayonet joints are employed to permit the ready replacement of cam surfaces. Such a system is shown, for example, in German Offenlegungschriften No. 1,938,891 published Oct. 15, 1970. In this arrangement, the cam retainers must be removed in order to enable the exchange or replacement of the cam carrier having the cam surface. While it is possible to preassemble the cam carrier having the cam surface on the cam retainer, this expedient necessitates the provision of a large stock of cam retainers and cam carriers, and as a consequence a considerable period of time is required for the supporting and locating of the desired elements.
U.S. Pat. No. 3,490,252 also discloses a cam system having a cam surface secured to a cam carrier. In this arrangement having the cam surface is exchanged or replaced externally by pulling the cam retainer from a bore. The locking of the cam carrier is effected by the use of a spring lock stopping system. This arrangement also has the disadvantage that it is necessary to maintain a large supply of cam carriers having different cam surfaces. Consequently, the arrangement necessitates the expenditure of considerable time to maintain the stock of cam carriers. In order to insure the rapid exchange or replacement of the carriers having different lock surfaces, it is thus necessary to employ costly techniques. In addition, the manufacture of the cam system of such an arrangement is very costly.
It is therefore the object of this invention to provide a cam system especially adapted for large circular knitting machines, that overcomes the above problems of previous cam systems, and that eliminates the time required for the sorting, locating and preparing of the system for the exchange or replacement of the cam carrier, as well as to reduce the necessity for a large stock of replacable elements and to reduce the unit costs of the elements employed.
The invention is directed to the provision of a cam system for circular knitting machines which employs easily fabricated elements as well as an economic arrangement of the cam system.